The contributing factors that led to heightened racial tensions during the 1906 Atlanta Race Massacre included:
A. Disputed land ownership case - Disputes over land and property ownership often inflamed tensions between white residents and the African American community.
B. Economic competition for jobs - Economic competition, especially in a time when jobs were scarce, heightened racial tensions as white citizens felt threatened by the economic progress of African Americans.
C. The construction of a new city park - The construction of public spaces and parks often involved disputes and could serve as a catalyst for racial tensions, although this factor was less significant than the first two.
D. Celebrations of cultural diversity in the city - While celebrations of cultural diversity could foster understanding, in this context, they may have been perceived negatively by some white residents, leading to increased animosity.
Overall, the most significant factors contributing to the racial tensions were economic competition for jobs and societal issues surrounding land ownership disputes.